When the Fuhrer sent U-boats to America waters in World War Two, he was repeating a strategy that the Kaiser had tried a generation earlier. Long neglected in the annals of military history is the first attempt to employ a fleet of undersea warships to help achieve world domination. While the Kaiser's surface navy was as ineffective against his enemies as the Fuhrer's surface navy, his use of German submarines, or U-boats, afforded a tactical advantage that was unprecedented in naval warfare. The Kaiser's unterseeboote took a great toll on the world's merchant vessels. The volume in hand is the first of its kind to compare Allied action reports with the deck logs and war diaries of German submarine commanders. These bipolar sources permit a true and accurate assessment of U-boat efficacy, while dispelling erroneous notions about the impact of submarine warfare against staunch American defenders. U-boats torpedoed and shelled harmless fishing vessels, plodding windjammers, and unarmed steamships. They laid mines off U.S. harbor approaches. They left sailors stranded hundreds of miles from shore without adequate food and water. They killed men and women indiscriminately. They took prisoners of war. One U-boat lobbed shells onto a beach on Cape Cod, Massachusetts. This was the first time since the War of 1812 that a foreign country attacked the American mainland. This is the trenchant story of U-boat aggression and American defiance in the Great War of atrocities, when people perished at sea or suffered incredible privation in their struggle to survive.